Dexmedetomidine and Ketamine for Preventing Delirium in Elderly Patients in the Intensive Care Unit: A Comparative Study
Year: 2025
Type: article
Study design: Clinical Trial
Abstract: INTRODUCTION: Delirium is a neuropsychiatric syndrome characterized by acute cognitive dysfunction and changes in attention, memory, and consciousness. According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), delirium is defined as a disturbance in attention and awareness that develops over a short period and fluctuates in severity, leading to changes in cognition, perceptual disturbances, and sleep- wake cycle disturbance. BACKGROUND: Delirium can occur in various medical conditions, including infections, drug toxicity, metabolic imbalances, and brain injury, it is prevalent in critically ill patients, particularly those in intensive care units (ICUs). Historically, the prevalence of ICU delirium is reported in 20% to 50% of patients with lower severity of illness,(2,3) but it can be as high as 60% to 80% in mechanically ventilated patients.(4–6) It is associated with increased morbidity, mortality, and long-term cognitive impairment. Delirium is a common concern among elderly intensive care unit (ICU) patients. Ketamine's effectiveness in preventing delirium remains controversial despite its demonstrated neuroprotective properties and cognitive benefits in previous studies. OBJECTIVES: To compare the effectiveness of dexmedetomidine and ketamine in preventing delirium among elderly ICU patients. To assess the incidence and severity of delirium in both treatment groups. To evaluate the safety profile and adverse effects associated with dexmedetomidine and ketamine. MATERIALS & METHODS: This randomized clinical trial involved 77 non-intubated patients aged over 65 years in a general ICU. The patients received low-dose intravenous ketamine (20 mg) or dexmedetomidine (0.2 μg/kg/h, titrated by 0.1 μg/kg/h). Delirium was assessed using the Richmond Agitation Sedation Scale (RASS) at 5, 10, and 15 minutes. The primary outcome was the percentage of patients achieving adequate sedation (RASS ≤ +1). The secondary outcome was time to reach adequate sedation. Adverse effects and physician satisfaction were evaluated after 60 minutes. RESULTS: No significant difference in delirium was observed between the groups after interventions or within each group over time. However, the ketamine group had significantly lower delirium incidence at 5 minutes. The percentage of patients achieving adequate sedation was higher in the Dexmedetomidine group (86.4%) than in the Ketamine group (36.4%) (P = 0.002). There was a delirium difference between groups at 10 minutes (P = 0.31) or 15 minutes (P = 0.082). Physician satisfaction did not differ significantly (P = 0.144). DISCUSSION: Managing delirium is a vital objective when caring for ICU patients, particularly the elderly population. Prolonged delirium is associated with elevated mortality rates and an increased likelihood of hospital readmissions (18). Previous studies have shown that brain volume and weight decreased with age (20-22), and structural and functional changes in brain regions, such as the hippocampus, have been reported in older populations (24-26). As a result, elderly patients experience a higher occurrence of delirium than other populations. Moreover, patients with delirium lasting less than 24 hours tend to have similar outcomes to those without delirium. (Therefore, the presen tstudy evaluated delirium in patients over 65 years. This open-label randomized clinical trial compared the safety and efficacy of low-dose ketamine to dexmedetomidine in the incidence and control of delirium among elderly ICU patients. The study showed no significant difference between the two treatment sinterms of delirium (basedon RASS scores) at different times (5, 10, and 15 minutes) after the intervention in older patients. This finding suggests that both ketamine and dexmedetomidine had a similar effect on delirium in this specific population. These findings indicate that when it comes to the primary outcome of reducing delirium, there was no advantage of using one medication over the other. Additionally, the present study did not show any significant side effects associated with either ketamine or dexmedetomidine treatment. The absence of significant side effects observed in the dexmedetomidine group is an important finding, indicating that low-dose dexmedetomidine was well tolerated by the elderly ICU patients in the trial. This is a positive outcome as it suggests that this medication canbe safely used in this context without causing significant adverse effects. Therefore, dexmedetomidine can be considered a safe option for managing delirium in this specific patient group. On the other hand, the study demonstrated a significant reduction in RASS scores within each treatment group at 5, 10, and 15 minutes, compared to the baseline of 0 minutes. This reduction in RASS scores indicated that low-dose ketamine was effective in reducing delirium among these patients. Therefore, the study concludes that dexmedetomidine was successful in achieving the desired outcome of reducing delirium severity in elderly ICU patients. Overall, based on the aforementioned findings, the study suggests that low-dose ketamine and dexmedetomidine have similar efficacy and safety profiles in the prevention and management of delirium among elderly ICU patients, and these results suggest that low-dose dexmedetomidine can be considered a viable option for the control of delirium in elderly ICU patients. The present study's findings contrast with those of Heydari et al.'s randomized clinical trial conducted in 2018. The aforementioned study demonstrated that the time required to achieve adequate sedation was significantly longer in the Dexmedetomidine group (0.2 μg/kg/h, titrated by 0.1 μg/kg/h) than in the ketamine group (4 mg/kg). However, there was no difference in sedation scores between the two groups 15 minutes after the intervention. CONCLUSIONS: The present study suggests that the administration of low-dose Dexmedetomidine to elderly ICU patients might reduce delirium incidence, supporting its beneficial effect for delirium control. KEYWORDS: Delirium, Ketamine, Dexmedetomidine, Elderly patients, ICU
Authors: Prosanjit Mazumder, Akm Habibullah, Md Shahidu Islam, Chandan Kumar Banik
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4410920872